There are known a process and a device for determining the amplitude, frequency and phase of oscillation in turbo-machine blades, based on the strain measurement of blades (Leontiev M. K. Strain measurement in aviation gas-turbine engines. Instructional manual—Moscow: MAI. 2001, pages 24-34—in Russian), consisting in the following: strain gauges are glued on the blades, the wires from the strain gauges are laid down along the blade, locking piece, wheel disc and shaft for leading them up to a particular current collector the signals of which are amplified and supplied to recording equipment.
The drawbacks of the known process and of the device for putting it into practice are as follows: a limited number of simultaneously checked blades and, as a result, an insufficient reliability of the blade oscillation parameter determination, as well as the impossibility to carry out strain measurements of blades in each turbo-machine unit.
The closest prior art for the present invention as to the technical concept is a process for determining oscillation parameters of turbo-machine blades, disclosed in the patent application GB1147737 published on Feb. 4, 1969 and consisting in the following: time intervals between the pulses of two contactless pulse detectors located in the plane of a turbo-machine wheel rotation are measured and the amplitudes of speeds and of translations of blade ends are calculated on the basis of said time intervals; then the frequency and the phase (with the precision of up to a decimal point) of the blade oscillations are determined and the maximum travels of the blade ends (deviations from the initial position) are statistically found for determining, with these results, the amplitude of the blade ends oscillations.
This known process is put into practice with a device disclosed in the patent application GB1147737 published on Feb. 4, 1969 and containing a unit of peripheral sensor (primary transducers), a sensor of full revolution of the turbo-machine working wheel and a sensor placed near the blade root, pulse shapers for said sensor, a unit for converting time intervals into a code, a control unit, an output register and an electronic computer.
The drawbacks of the known process and the device for putting the same into practice are as follows: a long time for making measurements and a complicated structure of the device due to the use of a high number of sensors. Otherwise, it is impossible to determine the initial oscillation phase for each blade.